Shares of the Sunnyvale, California-based company slid 5.3
percent to $19.14 at the close in New York, the biggest decline
since Oct. 24. The stock has fallen 12 percent in the past year.

Juniper’s sales and profitability are being threatened by
Alcatel-Lucent’s entry into the market for routers that sit at
the center of Internet providers’ networks, as well as Cisco’s
new Nexus 6000 switches and Palo Alto Networks Inc. (PANW)’s momentum
in security firewalls, Simona Jankowski at Goldman Sachs wrote
in a research note today. She cut her rating on Juniper stock to
sell from neutral, and lowered the price target to $17 from $21.

“We have greater concerns about Juniper’s ability to
execute in an environment marked by more rapid disruptive change
and heightened competition,” Jankowski wrote. The challenges
“include the potentially disruptive nature of the move to a
more software-oriented model, the impact on the balance sheet
from the accelerated pace of recent acquisitions, and higher
than average senior management turnover over the last three
years.”

Juniper’s primary business is selling networking equipment
to telecommunications-service providers, whose capital spending
has been inconsistent. While there are positive signs in that
area, spending on core Internet-routing gear may remain
sluggish, Jankowski wrote.

Bloomberg News reported in October that Juniper planned to
eliminate 500 jobs, or 5 percent of its workforce, to cut
expenses amid rising competition, citing people familiar with
the matter.